std::experimental::filesystem::path:: concat, std::experimental::filesystem::path:: operator+=

From cppreference.com
C++
Experimental
Filesystem library
Classes
Functions
File types
path
Member functions
Path decomposition
Non-member functions
path & operator + = ( const path & p ) ;
(1) (filesystem TS)
path & operator + = ( const string_type & str ) ;
(2) (filesystem TS)
path & operator + = ( const value_type * ptr ) ;
(3) (filesystem TS)
path & operator + = ( value_type x ) ;
(4) (filesystem TS)
template < class Source >
path & operator + = ( const Source & source ) ;
(5) (filesystem TS)
template < class CharT >
path & operator + = ( CharT x ) ;
(6) (filesystem TS)
template < class Source >
path & concat ( const Source & source ) ;
(7) (filesystem TS)
template < class InputIt >
path & concat ( InputIterator first, InputIterator last ) ;
(8) (filesystem TS)

Concatenates the current path and the argument.

1) Concatenates * this and p in such a way that native() of the result is exactly original native() concatenated with p. native ( ) .
2) Same as (1) , except the resulting native() is a concatenation of the original native() and the string str .
3) Same as (1) , except the resulting native() is a concatenation of the original native() and the null-terminated string whose first character is pointed to by ptr .
4) Same as (1) , except the resulting native() is a concatenation of the original native() and the single character x .
5) Same as (1) , except the resulting native() is a concatenation of the original native() and the sequence (which may be in portable or native format) represented by source , which may be std:: basic_string , null-terminated multicharacter string, or an input iterator pointing to a null-terminated multicharacter sequence.
6) Same as (4) , except that character conversion may be performed.
7) Same as (5) .
8) Same as (5) , except that the sequence is represented by any iterator pair that designates a multicharacter string.

Parameters

p - path to append
str - string to append
ptr - pointer to the beginning of a null-terminated string to append
x - single character to append
source - std:: basic_string , null-terminated multicharacter string, or an input iterator pointing to a null-terminated multicharacter sequence, which represents a path name (either in portable or in native format)
first, last - pair of LegacyInputIterator s that specify a multicharacter sequence that represents a path name
Type requirements
-
InputIt must meet the requirements of LegacyInputIterator .
-
The value type of InputIt must be one of the encoded character types ( char , wchar_t , char16_t and char32_t ).
-
CharT must be one of the encoded character types ( char , wchar_t , char16_t and char32_t ).

Return value

* this

Exceptions

May throw filesystem_error on underlying OS API errors or std:: bad_alloc if memory allocation fails.

Notes

Unlike with append() or operator/= , additional directory separators are never introduced.

Example

Run this code 
#include <experimental/filesystem>
#include <iostream>
namespace fs = std::experimental::filesystem;
 
int main()
{
    fs::path p1; // empty path
    p1 += "var"; // does not insert a separator
    std::cout << "\"\" + \"var\" == " << p1 << '\n';
    p1 += "lib"; // does not insert a separator
    std::cout << "\"\" + \"var\" + \"lib\" == " << p1 << '\n';
}

Output: 

"" + "var" == "var"
"" + "var" + "lib" == "varlib"

See also

appends elements to the path
(public member function)
concatenates two paths with a directory separator
(function)
Retrieved from " https://en.cppreference.com/mwiki/index.php?title=cpp/experimental/fs/path/concat&oldid=154865 "